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Regular Unleaded or Unleaded Plus???

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23K views 6 replies 6 participants last post by  satchel  
#1 ·
I've had my Insight for about 2 weeks (love it!). My question is about gasoline and the octane rating. The manual says that the car must use "87 or higher" (regular). The guys at the car dealership told me to ONLY use 89/Unleaded Plus. They acted like something devastating would happen. Prius-owning friends use either - some only do Plus, some only do Regular. What is better? I've only had to refill once so far and I put in Plus just to be safe.

What level is best for the car? And if I put in Regular, is this terrible? Am I doing longer term damage? (I'd love to put in Plus regularly but I'd also like to be cost-conscious.)

This is my first hybrid car. I live in southern California, if that matters regarding the best gas to use.
 
#2 ·
What level is best for the car? And if I put in Regular, is this terrible? Am I doing longer term damage? (I'd love to put in Plus regularly but I'd also like to be cost-conscious.)

This is my first hybrid car. I live in southern California, if that matters regarding the best gas to use.

87 is fine. Higher octane is only needed IF the car starts to ping or knock, like at high altitudes, ie: above 10,000 feet or so...

Burning 89 or 91 is a waste of money otherwise....any Honda dealer or tech that says otherwise needs to be fired or worse....:rolleyes:
 
#4 ·
wstander - Thanks for the input! That is what I suspected. This question has been bugging me. When I asked the guys at the dealership if it was okay to use 87, they were all "No, no, no...only use 89."

Brian - Thanks for referrring to that thread but I did skim through that thread before posting. The focus there was more on what BRAND of gasoline (Shell, Chevron, BP, etc) to buy from and the octane ratings people were throwing out were all over the place. The discussion is not pertaining strictly to octane rating which is my main question.
 
#5 ·
My understanding is that engines with higher compression ration need the higher octane, of "plus" gasoline. Perhaps the Honda people were thinking of their more performance orientated models?

Of greater concern to me has been the quality and price of the gasoline I buy. I've been finding poorer quality gas (lower mpg - poorer acceleration) sometimes at higher pump prices, at stations that have ground water leakage into the underground gas storage tank. Oregon has been using governmental regulation, over the complaints of the gas station owners association, to require replacement of old leaky underground gasoline storage tanks. So currently one can go to a low low priced gas station, with new underground tanks, and get good quality regular gas and get great mpg !
 
#6 ·
By the way, "Plus" fuel (at least in the upper midwest) uses 10% ethanol as the octane booster. Minnesota, at least and perhaps others, require all gas to contain 10% ethanol. Ethanol does not have as much energy per gallon, so if you are using "Plus" fuel, your mpg will be 2-3% lower. That amounts to about 1 mpg with the Insight. It also means that you should pay 2-3% less at the pump for "Plus". Unless it is more than 10 cents less, I don't buy it.
 
#7 ·
Your car should run fine on 87 octane as recommended. Modern cars have knock sensors which will detect engine knock and slightly retard the timing to compensate if necessary. At higher altitudes the lower atmospheric pressure actually deters knock. That's why you'll see 85 octane for sale in the mountains. It's not wise to burn it at lower altitudes because it could cause engine damage. Stick with 87 octane and avoid corn squeezings at all costs and you'll get the best mpg.
Octane rating - Wikipedia, the free encyclopedia
Gasoline gallon equivalent - Wikipedia, the free encyclopedia